JP2001325135A - Device and method for storing/reproducing data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that much time is required in the case of deleting all files in a directory. SOLUTION: A data storing/reproducing device is provided with a 1st memory for temporarily storing encoded data and writing/reading out the FAT data of a FAT area in a DOS format and a directory entry, a 2nd memory for storing the encoded data on the basis of the DOS format and a system controller for controlling the storage and reproduction of the encoded data and the deletion of the encoded data stored in the 2nd memory. The system controller reads out the directory entry written in the 1st memory in each sector or in each cluster in the case of deleting all files included in the directory, the read contents are changed, the contents of the FAT data are changed, and the directory entry and the FAT data are written in the 2nd memory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a DOS (Disk Operating System) used in a personal computer.
The present invention relates to a data storage / reproduction device and a data storage / reproduction method for writing and reading data using a storage medium managed by a format.

[0002]

2. Description of the Related Art Many personal computers use the DOS format to construct a file system on a recording medium such as a hard disk drive or a rewritable optical disk. In recent years, with the spread of personal computers, devices other than personal computers sometimes record data on a recording medium using the DOS format and reproduce the data recorded on the recording medium with the personal computer.

In the DOS format, data to be recorded is treated as a file, and the file is stored in a hierarchical structure (directory structure). DOS format is IPL
(Initial Program loader) area, FAT (File Alloc)
ation Table) area, root directory area, and data area.

FIG. 4 is a schematic diagram showing a logical structure of the DOS format. In FIG. 4, in the DOS format, data is managed by a sector number starting from “0” and a cluster number starting from “2”.

[0005] The IPL area stores a program for starting DOS, parameters relating to the structure of a recording medium, and the like.

The FAT area has a FAT12 for 12 bits and a FAT for 16 bits based on the bit length of the data.
There are types such as FAT32 for 16-bit and 32-bit. Here, the FAT16 for 16-bit will be described as an example. F
The AT area usually has a FAT (1) area and a FAT (2) area. The data stored in the FAT area is assumed to be FAT data.

In the FAT (1) area, the usage status of each cluster in the data area is stored using a 16-bit usage status code. The FAT (2) area is a backup area for the FAT (1) area, and stores the same data as the FAT (1) area data.

[0008] One or more directory entries are stored in the root directory area. In the DOS format, subdirectories can be created below the root directory, and a plurality of subdirectories and files can be created in the root directory.

A directory entry is information (file name, extension, attribute, reserved area, update time, update date, start cluster number, file size) about a subdirectory or file. Hereinafter, information about a subdirectory is referred to as a subdirectory entry, information about a file is referred to as a file entry,
Subdirectory entries and file entries are collectively called directory entries.

Here, the directory entry shown in FIG. 4 is determined based on the file attribute as a file entry or a subdirectory entry. When a flag is set in bits 3 and 4, the directory entry is a subdirectory entry. If it is determined that the entry is a directory entry, and the flag is not set in the bits 3 and 4, the directory entry is determined to be a file entry.

The data area stores the contents of subdirectories and files in cluster units.

A cluster is composed of a set of a plurality of sectors. Reading and writing of data are performed in cluster units. A 16-bit usage code shown in the FAT (1) area forms a cluster chain, and manages files having a size larger than one cluster and directory entries exceeding one cluster as a series of files and subdirectories. can do.

Here, since the root directory area is fixed, the number of files and subdirectory entries that can be registered in the root directory area is also limited. Since the subdirectory is recorded in the data area, the number of entries can be increased as long as the data area has a free space.

To delete a file or a subdirectory, the first byte of the file name of the file entry or the subdirectory entry is rewritten to "0E5h", and the usage code of the corresponding FAT area is changed to "000".
0h (unused cluster) ".

In the file entry and the subdirectory entry, the first byte of the file name is "0".
If it is "0h", it is regarded as an unused entry, and indicates that all subsequent entries are unused.

[0016]

When a DOS format storage medium is used in a personal computer,
Data is read from the storage medium and written to the storage medium via a DOS operated by a personal computer.

In addition to a personal computer,
For example, in a semiconductor memory storage / playback apparatus that stores an audio signal in a semiconductor memory and reproduces the stored audio signal, the semiconductor memory manages data in a DOS format.

In a data storage / reproduction device such as a personal computer or a semiconductor memory storage / reproduction device, when deleting all the files in a certain directory, the FAT data and the directory entry are sequentially deleted by one.
Work to delete one by one.

Since the data storage / reproduction device reads data from the storage medium and writes data to the storage medium in cluster units, when deleting all of a plurality of files registered in a certain directory, the data The processes of reading data from the storage medium and writing data to the storage medium in cluster units occur by the number of registrations. Therefore, in the case of a storage medium that takes a long time to access, it takes time to delete a file.

FIG. 5 is a schematic diagram for explaining the operation when all files in the directory are deleted. FIG. 5 (a)
As shown in the figure, when a plurality of files (file 1 to file N) exist in the directory A, the plurality of files are composed of a plurality of clusters M, and when all the files in the directory A are to be deleted, the The controller stores the directory entry of the storage medium in the RA.
After writing to an M (Random Access Memory), changing the contents of the directory entry in the RAM and deleting the file, the process of writing the directory entry in the RAM to the storage medium is repeated for the number of files.

When deleting all files in the directory A shown in FIG. 5A, the system controller
As shown in (b), the cluster 1 is read from the storage medium and written to the RAM, the file 1 of the cluster 1 is deleted, and the cluster 1 is read from the RAM and written to the storage medium.

Next, the cluster 1 is read from the storage medium again and written into the RAM, the file 2 of the cluster 1 is deleted, and the cluster 1 is read from the RAM and written into the storage medium.

When the deletion of the file of the cluster 1 is completed, the cluster 2 is read from the storage medium and written into the RAM, the file of the cluster 2 is deleted, and the cluster 2 is read from the RAM and written into the storage medium.

When the directory A is composed of a plurality of files N and the plurality of files N is composed of a plurality of clusters M, the system controller reads data from the storage medium and writes data to the storage medium. This must be performed for the number of files (M × N times).

In particular, the above-mentioned semiconductor memory storage / reproduction device is used at the time of an interview or the like as a portable device capable of storing an audio signal in a semiconductor memory by a microphone input or the like and reproducing the stored audio signal. . In such an apparatus, when an unnecessary portion of an audio signal stored in a semiconductor memory is deleted, if an audio signal deletion process takes a long time, a recording omission in an interview may occur.

When the number of files is very large and a cluster chain is formed, even if all the files in the directory are deleted, the chain remains, which may adversely affect the subsequent operation. For example, if you try to create a new file, you have to check many areas to see if the file name is duplicated,
take time.

Therefore, the present invention provides a data storage / reproducing apparatus which can reduce the time required to delete all files in a directory, and can increase the processing speed of operations after deleting files in a directory. It is an object to provide a data storage / reproduction method.

[0028]

According to a first aspect of the present invention, there is provided a first memory for storing encoded data and for writing and reading FAT data and directory entries in a DOS format; Second to store data based on DOS format
And a memory for controlling storage of the encoded data in the second memory and reproduction of the encoded data stored in the second memory, and deleting the encoded data stored in the second memory. In a data storage / reproducing apparatus provided with a system controller for controlling the number of files, when deleting all of a plurality of files in a directory, the system controller deletes the directory entry written in the first memory in units of sectors or clusters. After reading and changing the content in units, the content of the FAT data is changed, and the directory entry and the FAT data with the changed content are written into the second memory.

According to a second aspect of the present invention, in the data storage / reproducing apparatus according to the first aspect, when the directory entry forms a cluster chain, the system controller determines the cluster of the directory of the FAT data. It is characterized in that the content is changed to the content indicating that it is the last cluster in the cluster chain.

According to a third aspect of the present invention, there is provided a data storage and reproduction method for deleting all files stored in a DOS format and existing in a directory.
Reading an entry, deleting the read directory entry, and, if the current sector is the last sector of the current cluster,
Confirming whether or not there is a cluster chain by referring to the data, and rewriting the FAT data to contents having no cluster chain when the cluster chain exists and is not a subdirectory. .

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of a data storage / reproduction device of the present invention. In this embodiment, the storage medium is a semiconductor memory, and an audio signal is stored in the semiconductor memory by MPEG (Moving Picture Exposure).
(erts Group) -Audio and the like will be described as an example.

In FIG. 1, the data storage / reproduction device includes an input unit 101, an encoding unit 102, a decoding unit 103, an output unit 104, a first memory 105, and a first memory controller 1.
06, the second memory 107, the second memory controller 10
8. A system controller 109 is provided.

The input unit 101 includes an analog / digital converter and the like, converts an input audio signal from an analog signal to digital data (audio data), and outputs the digital data.

The encoding unit 102 encodes audio data output from the input unit 101 with high efficiency (for example, MP
EG-Audio, etc.) and output as encoded data.

The decoding unit 103 decodes audio data output from a first memory controller 106, which will be described later, and outputs decoded digital data.

The output unit 104 includes a digital / analog converter, etc., and converts digital data input from the composite unit 103 into an analog signal (audio signal) and outputs it.

The first memory 105 temporarily stores encoded data input from the encoding section 102 via the first memory controller 106, and also stores the encoded data from the second memory 107 to the second memory controller 108 and the first memory controller 106. And temporarily stores the encoded data input via the.

The first memory 105 also has a work area for file deletion processing and the like. In the first memory 105, the FAT data or the directory entry of the second memory 107 is written, and the reading and writing of the data by the file deletion processing and the like are performed.

The first memory controller 106 stores encoded data input from the encoding unit 102 in the first memory 10.
5, after a predetermined amount of encoded data is accumulated in the first memory 105, the encoded data is read from the first memory 105 and transferred to the second memory controller 108.

Further, the first memory controller 106
The second memory 107 is operated by the second memory controller 108.
The coded data read from the first memory 105 is written into the first memory 105, the coded data is read from the first memory 105 at a constant transfer rate, and transferred to the decoding unit 103.

Further, the first memory controller 106
The FAT data stored in the FAT area of the second memory 107 input from the second memory controller 108 is stored in the first memory 105, and the stored FAT data is read and written.
5 is transferred to the second memory controller 108 again.

The second memory 107 is a storage medium for storing encoded data obtained by encoding an audio signal with high efficiency, and is, for example, a semiconductor memory such as a flash memory. The second memory 107 stores the encoded data based on the DOS format. The DOS format is a well-known format used for a personal computer or the like, and thus a detailed description is omitted.

The second memory controller 108 controls writing of the encoded data input from the first memory controller 106 to the second memory 107, reads out the encoded data from the second memory 107, and controls the first memory controller 106 Transfer to

The system controller 109 includes a first memory controller 106 and a second memory controller 10
8 to temporarily store encoded data in the first memory 105 and then to store the encoded data in the second memory 107.
After the encoded data stored in the memory 107 is stored in the first memory 105, the encoded data is reproduced.

The system controller 109 controls the start and stop of storage of audio signals (encoded data) based on an instruction signal from an operation unit (not shown).
Alternatively, the reproduction of the audio signal (encoded data) is started or stopped, and the control of deleting the encoded data stored in the second memory 107 is performed.

When deleting the encoded data stored in the second memory 107, the system controller 109 controls the second memory controller 108 to
The FAT data and the directory entry in the second memory 107 are read, and the first memory controller 106 is controlled to store the read FAT data and the directory entry in the first memory 105.

Then, the system controller 109
The FAT data and directory entry stored in the first memory 105 are changed, the encoded data (file) stored in the second memory 107 is deleted, and the contents are controlled by controlling the first memory controller 106. Is read from the first memory 105 and the second memory controller 108 is controlled to write the FAT data and the directory entry in the FAT area and the root directory area or the data area of the second memory 107.

An operation of storing an audio signal in the data storage / reproduction device of the present embodiment will be described. The input audio signal is converted into digital data by the input unit 101, and then is encoded by the encoding unit 102 with high efficiency. The encoded data output from the encoding unit 102 is
The data is sequentially written to the first memory 105 by the first memory controller 106.

When a predetermined amount of encoded data is stored in the first memory 105, the first memory controller 106
Thus, the encoded data is read from the first memory 105 and transferred to the second memory controller 108. First
The encoded data transferred from the memory controller 106 is written to the second memory 107 by the second memory controller 108 according to the DOS format.

The operation of reproducing the audio signal in the data storage / reproduction device of this embodiment will be described. A request to reproduce an audio signal is sent to the system controller 1 by the operation unit.
When the value is 09, the system controller 109 causes the second memory controller 108 to read the encoded data from the second memory 107. The encoded data read from the second memory 107 is transferred to the first memory controller 106 by the second memory controller 108.

The encoded data transferred from the second memory controller 108 is
6 is written to the first memory 105. The encoded data written in the first memory 105 is read from the first memory 105 at a fixed transfer rate by the first memory controller 106 and transferred to the decoding unit 103. The encoded data is decoded by the decoding unit 103,
The output unit 104 converts the digital data into an analog signal and outputs it as an audio signal.

The operation for deleting all the encoded data (files) in the directory stored in the second memory 107 will be described. FIG. 2 is a flowchart for explaining data deletion processing in one embodiment of the data storage / reproduction method of the present invention. From the operation unit, the second memory 10
When an instruction to delete all the files stored in a certain directory is issued, the system controller 10
9 reads the FAT data in the second memory 107 by controlling the second memory controller 108 and writes the FAT data in the first memory 105 by controlling the first memory controller 106 (step 201).

In order to shorten the processing time of file deletion, rewriting of the FAT data is performed on the FAT data written in the first memory 105. Second memory 10
7 is generally written at a lower speed than a memory such as a RAM.
Rewriting the T data directly increases the time spent on file deletion.

The system controller 109 controls the second memory controller 108 to read the file entries of each file sequentially from the head sector of the current directory in the second memory 107 and write them in the first memory 105 (step 202).

The system controller 109 deletes each file entry while confirming whether or not the file entries written in the first memory 105 are in the entry order (step 203).

To delete a file entry, change the first byte of the file name of the file entry to “0E5h”.
It is done by changing to. As a result, the file of the file entry is deleted.

After deleting the file entry, the system controller 109 checks whether the current sector is the last sector of the current cluster (step 205). If the current sector is not the last sector, the processing from step 202 to step 205 is repeated.

If the current sector is the last sector, it is checked whether there is a next cluster (cluster chain) following the current cluster by referring to the FAT data written in the first memory (step 206). ).

If there is a cluster chain, the position of the head sector of the corresponding cluster is calculated, and the processing from step 202 is repeated.

If a cluster chain does not exist, it is confirmed whether or not a cluster chain has existed even once in the processing so far (step 207). If there is no cluster chain, the contents of the FAT data written in the first memory 105 are changed and then read, and overwritten on the FAT data already written in the second memory 107 (step 208). .

If a cluster chain exists even once, it is checked whether a subdirectory exists (step 209). If the subdirectory exists, the contents of the FAT data written in the first memory 105 are changed and then read out, and overwritten on the FAT data already written in the second memory 107 (step 208).

If the subdirectory does not exist,
Since all the files in the directory have been deleted by the above-described processing, the F written in the first memory 105 is deleted.
The AT data is rewritten to have no cluster chain (step 210), and is overwritten on the FAT data already written in the second memory 107 (step 20).
8).

Next, the operation of the file deletion shown in step 203 in the flowchart shown in FIG. 2 will be described. FIG. 3 is a flowchart for explaining the operation of the file deletion process in the data storage / reproduction method of the present embodiment. The file deletion process proceeds one entry at a time from the first sector.

It is confirmed whether the file entry is a valid entry (step 301). The file attribute of the file entry is not the subdirectory attribute (bit “4”), and the first byte of the file name is “00h (unused directory entry)” or “0”.
If it is other than "E5h (deleted directory entry)", it is determined to be a valid file entry.

In the case of a valid file entry, the first byte of the file name is changed to "0E5h", and the file entry is changed to the deleted file entry (step 302).

The start cluster number of the file entry is checked. If the start cluster number is other than "0", the FAT data is checked, and the contents are changed to a content without a cluster chain (step 303).

At this stage, it is confirmed whether or not all entries have been deleted (step 306). If any entries remain, the processing from step 301 to step 306 is repeated.

If there is no valid file entry in step 304, a valid subdirectory
Check if it is an entry. If the entry is a valid subdirectory entry, a flag indicating that a subdirectory entry exists is set (step 3).
05), which is used in the processing of step 209 shown in FIG.

If there is no valid subdirectory,
Proceed to step 306.

As described above, when deleting all the files in a certain directory, the system controller 109 performs the file deletion processing not in file units but in sectors or clusters storing a plurality of files. The number of accesses to the second memory 107 decreases,
High-speed processing is possible.

When the directory is discontinuously stored in the second memory 107 by the cluster chain, by initializing the cluster chain, the inside of the directory after deleting all the files is confirmed, and the processing is performed. It is possible to prevent time from being taken.

[0072]

According to the present invention, the time for deleting all the files in the directory can be reduced, and the processing speed of the operation after deleting the files in the directory can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of a data storage / reproduction device of the present invention.

FIG. 2 is a flowchart illustrating data deletion processing in one embodiment of the data storage / reproduction method of the present invention.

FIG. 3 is a flowchart for explaining the operation of a file deletion process in the data storage / reproduction method of the embodiment.

FIG. 4 is a schematic diagram showing a logical structure of a DOS format.

FIG. 5 is a schematic diagram illustrating an operation when all files in a directory are deleted.

[Explanation of symbols]

101: input unit, 102: encoding unit, 103
..Decoding section, 104 ... output section, 105 ... first
Memory, 106... First memory controller, 107
... second memory, 108 ... second memory controller, 109 ... system controller.

Claims (3)

[Claims] A first memory for storing encoded data and for writing and reading FAT data and directory entries in a DOS format; a second memory for storing the encoded data based on a DOS format; It controls the storage of the encoded data in the second memory and the reproduction of the encoded data stored in the second memory, and controls the deletion of the encoded data stored in the second memory. In the data storage / reproducing apparatus provided with a system controller, the system controller reads the directory entry written in the first memory in sector units or cluster units when deleting all of a plurality of files in a directory. After changing the contents of the FAT data, The directory in which you change the content and
A data storage / reproduction device for controlling writing of entries and FAT data to the second memory. 2. The data storage / reproducing apparatus according to claim 1, wherein said system controller comprises:
If the entry forms a cluster chain, the FA
A data storage / reproducing apparatus for changing a cluster of the directory of T data to a content indicating that the cluster is the last cluster of a cluster chain. 3. A data storage / reproduction method for deleting all files stored in a directory stored in a DOS format, comprising: reading a directory entry of each file in order from a first sector of the directory; A step of deleting an entry, a step of referring to FAT data in the FAT area when the current sector is the last sector of the current cluster, and a step of confirming whether or not there is a cluster chain; The F
Rewriting the AT data to contents having no cluster chain.